Gas turbine power plant



April 23, 1946. J. LARRECQ 2,399,046

GAS TURBINE POWER PLANT Filed March 26, 1940 Inventor: thonylLavrecq,

His Attorney.

Patented Apr. 23, 1946 UNITED STATES, PATENT OFFICE GAS TURBINE POWER PLANT Anthony J. Larrecq, Marblehearl, Mass assignmto General Electric Company, a corporation of New York Application March 26, 1940, Serial No. 325,998

3 Claims.

vide an improved construction and arrangement of gas turbine power plants whereby such plants assume a minimum space and ma be operated effectively and economically.

For a consideration of other objects and of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing Fig. 1 illustrates a gas turbine power plant partly in section in accordance with my invention, Fig. 2 shows the location and arrangement of such plant on an aircraft; and Fig.

3 is an enlarged view of a part of Fig. 1.

The arrangement comprises a gas turbine ill for driving a compressor II and a propeller l2 of an aircraft. The turbinein accordance with my invention includes two sets of bucket wheels, one set consisting of two bucket wheels [3 and I4, and a second set consisting of a single bucket wheel ii. The two sets are mechanically independent, that is, the two sets of wheels are secured to independent hollow shafts i6 and I1 respectively. The wheels l3 and II have solid disks securely held together and fastened to a flange l3 formed on the hollow shaft It by means of a plurality of bolts or pins l9. The shaft l6 serves for driving the compressor aswill be more fully explained hereinafter. The disk of the bucket wheel I5 is secured to a flange 20 of the hollow s aft i! by means of a p urality of p ns 2 I. The shaft I1 is arranged to drive the propeller l2 as will be explained more fully hereinafter.

The turbine III has an outer shell or casing 22 and an inner shell or casing 23 made up of several sections flanged together and suitably secured to and supported on the outer casing. The inner and outer casings 22, 23 form a double wall surrounding the hi her turbine stages including the bucket wheels I3, I to break up temperature and pressure drop across the individual casing. The last turbine wheel I5 is located inside a double walled exhaust casing 24 which has a rearwardly directed discharge conduit 25. The inner wall of the double walled exhaust casing 24 is secured to and supported on the outer turbine casing 22 by means of a flanged ring 28. The turbine shown is an internal combustion turbine, that is, one in which combustion of fuel takes place within combustion chambers formed inside the turbine casing. To this end the outer and inner turbine casings22 and 23 are provided with concentrically spaced extensions 21 and 23.

These extensions together with spaced cylindrical walls 28, .30 and an end wall 3| form a ring space accommodating and enclosing a plurality of spaced combustion chambers 32. Each combustion chamber is formed by a substantiall cylindrical element open at both ends and spaced from and supported on the walls 28 and 23 and with an axis parallel to the axis of the turbine. Fuel is injected into the right-hand end of the chamber 32 by means including fuel injection nozzles 33 supported on a web 33a and connected to fuel supply conduits 34 projecting through an end portion of the outer casing extension 21. Each chamber 32 includes known means such as a spark plug 32a for initiating combustion during starting operation.

Air is supplied to the right-hand end of the ring space formed between the walls 21 and from the discharge end of the compressor or blower I I. Part of this air flows into the inlet of the combustion chamber or cylinder 32 and mixes with the fuel discharged from the nozzle 33 and in view of its high temperature effects ignition and combustion of the latter. A part of the air passes through the space formed between the wall of the combustion cylinder 32 and the walls 28 the gases discharged from the left-hand end of the chamber 32, effecting combustion of unburned fuel. Another part of the air flows through the space formed between the walls 29 and 30, thereby reducing radiation of heat towards the shaft Hi. This air is dischar ed from the left-hand end of said space through openings 35 towards the rim of the disk of the first stage bucket wheel H, thereb cooling the disk and the buckets secured thereto. The combustion gases discharged from the chamber or chambers 32 are conducted to and properly directed towards the buckets of the first stage wheel H by a nozzle plate or diaphragm formed by partitions 36 secured to inner and outer bands, which latter are in turn secured to and supported on the walls 21! and 29 adjacent the buckets of the first wheel I 4.

The bucket wheel I and the nozzle plate or diaphragm 38 form the first turbine stage. The

second stage of the turbine includes the second bucket wheel l3 together with a diaphragm 31 located between the wheels [3, l4 and including an annular roW of partitions 38 having ends se cured to inner and outer bands 39 and 40 respectively. The outer band 40 is supported on the inner casing or shell 23. The inner band 39 is fused to a disk to reduce leakage of fluid along the adjacent sides of the wheels l3 and [4. In order to make this disk as light as possible it is made up of two rings or plates 4! and 42 with a spacer 43 fused between the outer ends of the plates and a sealing ring 44 fused to the inner ends of the plates (see Fig. 3). Intermediate portions of the two plates 4| and 42 are reinforced by rings 45 welded to the adjacent sides of the plates. The rings engage each other and prevent collapsing of the hollow disk.

The gases discharged from the bucket wheel l3 during operation are conducted to the bucket wheel 15 by means including a nozzle diaphragm 46. This nozzle diaphragm has an annular row of nozzles formed by a partition structure 41. The structure 41 is supported at its outer end on the turbine casing and is secured at its inner end to a disk 48. The disk 48 similarly to the disk of the diaphragm of the second stage is made up of two halves, that is, of two plates which have central portions 49 engaging each other and outer portions spaced apart and having edges fused to a spacer ring 58. The partition structure 41 is fused to the left-hand portion of the spacer ring 50 so that the left-hand edges of the partitions are in close proximity to the buckets of the wheel l whereas the right-hand edges are considerably axially spaced from the buckets of the wheel l3. The ring space thus formed between the buckets of the wheel I; and the partition structure 41 serves as a reheat chamber for the gases discharged by the bucket wheel 13. The reheating is accomplished by the injection of fuel into the ring space by means including a plurality of nozzles 5| disposed in said ring space and arranged to receive fuel under pressure from a source, not shown. From another viewpoint, the ring space formed between the bucket wheel l3 and the bucket wheel l5 constitutes a combustion chamber for the turbine wheel or low pressure part l5 of the turbine arrangement, fuel being injected into said chamber at several points and the combustion of the fuel being effected by combustion gases and air discharged from the high pressure part of the turbine.

The propeller I2 is driven from the low pressure turbine shaft ll through the intermediary of a gearing. This gearing includes a pinion 55 having teeth formed on the shaft I1 and engaging gearing means including a gear 56 which in turn meshes with an internal gear 51. The gear 51 is secured to a hollow shaft 58 telescoping an end portion of the turbine shaft I1 and constituting the propeller shaft. The shaft I1 is supported on a bearing 59 held on a stationary wall 60. The propeller shaft 58 is supported on a bearing 6| which in turn is held on a wall 62. The walls 60 and 62 have flanged portions 53 fastened to and supported on a hood structure 64. The latter has a reinforced, slightly conically-shaped portion surrounding the turbine and acting as a support for the latter as well as for the compressor. The front portion of the hood 64 has openings 64a for admitting cooling air to the space between the hood and the turbine casing. The turbine exhaust casing 24 has a central opening 64b surrounding the shaft. Cooling air is admitted through the opening 64b in the outer wall of the exhaust casing to pass through the space formed by the double wall of the exhaust casing.

The propeller shaft is supported at its righthand end by a second bearing 65 held on a wall 66. The gear 56 rotates about a shaft 61 held on its outer ends on the walls 60 and 66.

The compressor II, as stated above, is driven from the high pressure part of the turbine by the hollow shaft IS. The compressor includes three stages 10, H and 12. Each stage has an impeller wheel 13 secured to and driven from the hollow shaft I6 and a diffuser T4 for converting velocit energy of the air impelled by the impeller 13 into pressure energy. The outer casing of the compressor is made up of several sections flanged and secured together by bolts 15. The inlet section of the casing forms an inlet chamber 16 with two openings 11 connected to inlet conduits 18. As indicated in Fig. 2, the two inlet conduits are located on opposite sides and each one is formed by a channel in a wing and opens in the direction of the propeller slipstream of the aircraft. The air compressed in the first stage is conducted to the inlet of the second stage by a channel 19 formed by a portion of the outer casing and a partition between the first and the second stage. Similarly, the air discharged from the second stage is conducted to the third stage by a channel 8| formed be-- tween the outer casing and a partition 82 between the second and the third stage. The air discharged from the third or last stage is conducted to the combustion chambers 32 and the ring space surrounding the latter by a channel 83 formed between a portion of the outer compressor casing and an end wall 84 of the compressor. The partitions 80, 82 and 84 form small clearances with the shaft and are supported on the outer casing by webs 85, 86 and 8! respectively.

The compressor shaft I6 is supported on two bearings, a bearing 88 located between the first turbine stage and the last compressor stage and a combined guide and thrust bearing 88 near the inlet end of the compressor. The bearing 88 is vented to atmosphere through a channel 89a.

A starting motor 90 is flanged to the righthand end of the compressor casing for rotating the compressor shaft [6 during starting operation.

During starting operation the compressor is rotated by the starting motor 80. As soon as a certain speed of the compressor and consequently a certain pressure at the discharge of the compressor have been attained, fuel is injected into the combustion chambers 32 and ignited at the start by an electric spark to effect combustion and operation of the turbine by the combustion gases. Whenever high load output of the low pressure turbine part including bucket wheel [5 is desired, fuel is injected through the nozzles 5| and at the start ignited by an electric sparking device 5 la to effect reheating of the combustion gases discharged from the high pressure turbine part. Such high load output in case where the low pressure part operates the propeller of an aircraft is necessary during starting and climbing of the aircraft.

The compressor also serves as a source for supercharging a passenger cabin or other sealed chamber or like consumer (not shown) requiring cacao-1e air under pressure during operation. In case of supercharged passenger cabin on an aircraft, increasing air pressure is required with increasing altitude. In order to obtain such increased supercharging of a cabin or like sealed chamber, I provide valved conduit means for connecting such cabin or chamber to either of the several compremor stages. In the present instance I have shown three conduits 9i, 9! and 93 connected to the low pressure, intermediate and high pressure compressor stages respectively and a multi-way valve 94 for connecting either of said conduits to a supply conduit 98 for a cabin or chamber to be supercharged. In the instance shown the valve 94 connects the conduit 92, that is, the second stage of the compressor, with the supply conduit 85. In case the aircraft increases its altitude and increasing supercharging of the cabin is required, the supply conduit 95 may be connected to the last compressor stage by turning the valve 94 in clockwise direction and vice-versa, with decreasing altitude and less supercharging required, the supply conduit 08 may be connected with the low pressure compressor stage or completely disconnected from the compressor by turning the valve in counterclockwise direction.

What I claim as new and desire to secure by Letters Patent 01 the United States is:

1. Internal combustion gas turbine comprising a double-walled casing, a bucket wheel, a nozzle plate for directing combustion gases to the wheel, a plurality of circumierentially spaced combustion chambers ahead of the nozzle plate, means including an extension of the casing and an inner double wall enclosing the combustion chambers, and fuel and air supply means connected to the combustion chamber, said inner double wall forming a channel for conducting cooling air from the air supply means to the rim of the bucket wheel.

2. An aircrait including a gas turbine having an inner and an outer casing with cylindrical concentrically spaced extensions at the inlet, a plurality of circumferentially spaced combustion chambers disposed within the inlet and a compressor driven from the turbine and having a discharge end connected to supply air to said combustion chambers and cooling air to the space formed between said cylindrical extensions and air under pressure to a consumer.

3. An aircraft including a gas turbine having an inner and an outer casing with cylindrical concentrically spaced extensions at the inlet, a plurality of circumierentially spaced combustion chambers disposed within the inlet and a multistage compressor driven from the turbine and having a discharge end connected to supply combustion air to the combustion chambers and cooling air to the space formed between said cylindrical extensions, and means including a plurality of conduits connected to separate stages and a valve for selectively discharging air from any of such stages.

ANTHONY J. LARRECQ. 

